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net: skbuff.c cleanup 

(skb->data - skb->head) can be changed by skb_headroom(skb)

Remove some uses of NET_SKBUFF_DATA_USES_OFFSET, using
(skb_end_pointer(skb) - skb->head) or
(skb_tail_pointer(skb) - skb->head) : compiler does the right thing,
and this is more readable for us ;)

(struct skb_shared_info *) casts in pskb_expand_head() to help memcpy()
to use aligned moves.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2010-09-01 05:25:10 +00:00 committed by David S. Miller
parent 86cac58b71
commit 6602cebb5b
1 changed files with 15 additions and 32 deletions
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47
net/core/skbuff.c
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@ -685,16 +685,10 @@ static void copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t gfp_mask)
{
int headerlen = skb->data - skb->head;
/*
* Allocate the copy buffer
*/
struct sk_buff *n;
#ifdef NET_SKBUFF_DATA_USES_OFFSET
n = alloc_skb(skb->end + skb->data_len, gfp_mask);
#else
n = alloc_skb(skb->end - skb->head + skb->data_len, gfp_mask);
#endif
int headerlen = skb_headroom(skb);
unsigned int size = (skb_end_pointer(skb) - skb->head) + skb->data_len;
struct sk_buff *n = alloc_skb(size, gfp_mask);
if (!n)
return NULL;
@ -726,20 +720,14 @@ EXPORT_SYMBOL(skb_copy);
struct sk_buff *pskb_copy(struct sk_buff *skb, gfp_t gfp_mask)
{
/*
* Allocate the copy buffer
*/
struct sk_buff *n;
#ifdef NET_SKBUFF_DATA_USES_OFFSET
n = alloc_skb(skb->end, gfp_mask);
#else
n = alloc_skb(skb->end - skb->head, gfp_mask);
#endif
unsigned int size = skb_end_pointer(skb) - skb->head;
struct sk_buff *n = alloc_skb(size, gfp_mask);
if (!n)
goto out;
/* Set the data pointer */
skb_reserve(n, skb->data - skb->head);
skb_reserve(n, skb_headroom(skb));
/* Set the tail pointer and length */
skb_put(n, skb_headlen(skb));
/* Copy the bytes */
@ -791,11 +779,7 @@ int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail,
{
int i;
u8 *data;
#ifdef NET_SKBUFF_DATA_USES_OFFSET
int size = nhead + skb->end + ntail;
#else
int size = nhead + (skb->end - skb->head) + ntail;
#endif
int size = nhead + (skb_end_pointer(skb) - skb->head) + ntail;
long off;
BUG_ON(nhead < 0);
@ -810,13 +794,12 @@ int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail,
goto nodata;
/* Copy only real data... and, alas, header. This should be
* optimized for the cases when header is void. */
#ifdef NET_SKBUFF_DATA_USES_OFFSET
memcpy(data + nhead, skb->head, skb->tail);
#else
memcpy(data + nhead, skb->head, skb->tail - skb->head);
#endif
memcpy(data + size, skb_end_pointer(skb),
* optimized for the cases when header is void.
*/
memcpy(data + nhead, skb->head, skb_tail_pointer(skb) - skb->head);
memcpy((struct skb_shared_info *)(data + size),
skb_shinfo(skb),
offsetof(struct skb_shared_info, frags[skb_shinfo(skb)->nr_frags]));
for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)